The effect of parameters of the CL-20 crystallization process carried out by solvent removal by evaporation in vacuo on shape, polymorph type, crystal size, and on their shock sensitivity was studied. The CL-20 crystallization process by this technique was shown to allow a precise control of the crystallization process parameters and of the process run. The o-xylene/ ethyl acetate system proved to be highly effective. Selecting suitable values of the parameters such as: pressure, process time, temperature, stirring rate, CL-20 crystals were obtained in the epsilon form (even with no need for inoculation of the crystallization system with polymorph epsilon seeds) and of the shape close to a spherical one. The crystal growth modifiers added allowed to additionally control the shape and size of the CL-20 crystals formed and to produce crystals of reduced impact and friction sensitivity.